This invention pertains to surgical cement mixing and delivery systems. More particularly, this invention relates to a self-evacuating base unit for a surgical bone cement mixing and delivery system.
There exist a number of applications where it is required to efficiently and thoroughly mix a binding material such as an adhesive or a cement that is formed from multiple components. For such applications, it is desirable to minimize the presence of air bubbles introduced within the adhesive during the mixing process. In many cases, the presence of air bubbles in the adhesive can weaken the resulting material that is formed by curing the adhesive.
One application is in the field of orthopedic surgery where an adhesive, in the form of surgical bone cement, is frequently used. Surgical bone cement typically comprises a two-part monomer polymer, such as methyl methacrylate. The use of surgical bone cement when performing orthopedic surgery has long been known. Numerous surgical procedures require the use of surgical bone cement. One exemplary procedure involves the installation of an artificial hip joint into a patient where the superior end of the patient""s femur is removed, and surgical bone cement is delivered into the resulting femoral cavity, prior to inserting a stem of the implant into the femoral canal. Additionally, another known procedure involves packing surgical bone cement around an implant component, such as when performing an acetabular construction by securing an acetabular cup of a hip joint replacement system into a hip socket using surgical bone cement.
In most orthopedic applications where surgical bone cement is used, time is of the essence when mixing and delivering surgical bone cement because such cement is formed from at least two components which are mixed together, and which generate heat when mixed so as to initiate imminent curing and hardening of the cement. However, such process occurs relatively quickly, which means that mixing and delivery tools must operate efficiently so that the bone cement does not cure before a surgeon is able to deliver the cement to a desired surgical site.
Stationary surgical cement mixing apparatus are known. Such apparatus form automated mixing stations that are relatively large and relatively immovable. For example, computer-controlled apparatus are known in the art for performing mixing and applying a vacuum within a mixing chamber. However, such surgical cement mixing apparatus are not portable, lightweight, and of relatively low-cost construction. Furthermore, such surgical cement mixing apparatus cannot be hermetically sealed and pre-packaged for disposable, single use within a surgical operating environment. Instead, such apparatus must be cleaned after each use, and can only be sterilized by autoclaving the apparatus. Furthermore, the apparatus cannot be readily moved from one desired location to another desired location.
U.S. Pat. No. 5,797,679 discloses one disposable surgical cement mixer apparatus having a base containing vacuum nipples that communicate with one another and that protrude from the base on opposite sides. One nipple is connected to a conventional vacuum source that is provided externally of the cement mixer apparatus. The other nipple is connected via a piece of plastic tubing with a cement mixing chamber of the mixer apparatus. In this way, a sub-atmospheric pressure can be applied within the mixing chamber during a mixing operation. However, such mixer apparatus requires the use of a conventional vacuum source which is located externally and separate from the apparatus. Accordingly, it becomes necessary to use the mixer apparatus in close proximity with an external vacuum source. Such proximity requirement significantly limits the mobility of the mixer apparatus. Additionally, it is necessary to connect a vacuum tube between the mixer apparatus and the external vacuum source. The presence of such tube during surgery is undesirable because the tubing restricts movement of the mixer apparatus within a surgical operating room. Furthermore, the tubing presents a hazard for personnel during such surgery resulting from potential entanglement of the tubing with personnel and equipment. Furthermore, since such mixer apparatus should be sterile, the act of physically connecting the mixer apparatus with an external vacuum source provides an opportunity for undesirable contamination.
A disposable support base and mixing system includes an improved apparatus for mixing binding materials such as adhesives and two-part cements, including acrylic surgical bone cement which is adapted to fix a surgical repair element to a patient""s hard tissue or bone. The base of the mixing system includes a vacuum source which is self-contained within the base in order to facilitate unencumbered and portable use of the mixing system within a surgical operating environment, and further to ensure that the mixing system remains sterile during deployment and use within the surgical operating environment. Even furthermore, such base ensures unencumbered use as the vacuum source is self-contained within the base which enhances pre-packaging within a sterile package. Even further uses are potentially available for mixing adhesives, such as multiple-component epoxies, for use in other non-medical applications. All of the above features are provided in an apparatus and support base that is relatively small, portable, lightweight, disposable, and of relatively low-cost construction.
According to one aspect, a disposable base for a surgical cement mixing system includes a support member and a vacuum source. The support member is configured to support cement within a mixing chamber. The vacuum source is carried by the support member. The vacuum source is operative to impart a relative vacuum within the mixing container during mixing of the cement.
According to another aspect, a portable binding material mixing base includes a support base and a vacuum source. The support base includes a housing. The vacuum source is provided in the housing. The vacuum source is operative to impart a vacuum to a binding material during mixing.
According to yet another aspect, a portable surgical bone cement mixing system includes a hollow base, a mixing container, and a vacuum pump. A mixing container is supported by the base. The vacuum pump is carried within the base. Furthermore, the vacuum pump is configured to apply a relative vacuum within a mixing chamber of the mixing container.